This sensitive bio-monitoring circuit was found in the December 1984 issue of Radio Electronics magazine. The circuit is powered by a 9 V battery and uses a low-impedance headphone output.
This circuit was found in a 1982 documentation. It uses only one integrated circuit and can be...
Only those who know the secret activation code will be able to turn on the device connected to...
This 2 meter (144 MHz) preamplifier is intended for use with portable transceivers. The...